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   FOUS11 KWBC 242008   
   QPFHSD   
      
   Probabilistic Heavy Snow and Icing Discussion   
   NWS Weather Prediction Center College Park MD   
   308 PM EST Sat Jan 24 2026   
      
   Valid 00Z Sun Jan 25 2026 - 00Z Wed Jan 28 2026   
      
      
   ...Ongoing major winter storm to bring crippling icing,=20   
   significant sleet, and heavy snow from the Southern Rockies/Plains=20   
   through the Southeast and up the Atlantic Coast into New England...   
      
   Meteorological Overview...   
   Forecast remains on track as a massive winter storm, set to=20   
   produce a swath of heavy snow, significant sleet, and dangerous ice   
   accumulations, continues across the Southern Plains and begins to=20   
   expand into the Ohio and Tennessee Valleys this afternoon. By=20   
   tonight, wintry precipitation is expected to lift into the Mid-=20   
   Atlantic, and reach New England on Sunday. By the time this event=20   
   winds down late Monday, it will leave a trail of more than 2000=20   
   miles of wintry precipitation, in a nearly continuous path, from=20   
   New Mexico to Maine.   
      
   The driver of this event will be the interaction of a northern   
   stream trough diving out of Canada with a southern stream impulse   
   ejecting from near Baja California. As these features move eastward   
   through the weekend and interact into a more amplified and larger   
   trough over the eastern CONUS, impressive subtropical moisture=20   
   will spread east/northeast both from the Pacific and the Gulf, with   
   IVT exceeding the 97th climatological percentile according to   
   NAEFS. The rich moisture from the south will accompany strong=20   
   850-700mb WAA that results in classic over-runing along an area of=20   
   850-700mb FGEN stretching from atop the Southern Plains to the TN=20   
   VLY and southern Mid-Atlantic by tonight, reaching New England   
   Sunday, and then finally exiting the Atlantic Coast on Monday. In   
   addition to the classic overrunning/WAA precipitation, the   
   placement of the upper jet as it strengthens and pivots poleward,   
   will support intense bands of snowfall (cross sections suggest a   
   high threat for CSI and even potential CI within the strongest WAA)   
   which will support snowfall rates of 1-2+"/hr at times where it is   
   all snow, and intense sleet/freezing rain rates in mixed zones.   
      
   Farther to the east, an intense CAD (Cold Air Damming) signature=20   
   will develop east of the Appalachians, with intense dewpoint   
   depressions of 20-30F during precipitation overrunning. While it   
   will take a while to saturate this to result in precipitation at   
   the surface, the intensity of this high with cold isallobaric   
   drainage aided both by mid-level confluence to the north and   
   precipitation falling into this wedge will enhance the CAD and   
   result in long duration mixed precipitation as the WAA pushes a   
   warm nose aloft (generally 800-700mb). This will support heavy   
   icing and sleet lifting northward into the Mid-Atlantic on Sunday,   
   and potentially as far as the south coast of New England as well.   
      
   With intense IVT pushing PWs to above the 99th percentile, there   
   will be plentiful moisture to work with everywhere from Texas   
   through New England. This will support heavy precipitation   
   accumulations regardless of p-type, so substantial impacts are   
   expected for a large swath of the nation. The heaviest snow is   
   expected from the Ohio Valley into the Northeast (more outlined   
   below), but an impressive jet-forced band of snow is also likely   
   from the Texas Panhandle through the Mid-Mississippi Valley.   
   Farther south, crippling icing is expected for parts of   
   AR/LA/MS/TN, as well as the Carolinas, with exceptional sleet   
   accumulations of several inches progged in between the snow and ice   
   from Arkansas through Kentucky, and then for portions of the Mid-   
   Atlantic as well.\   
      
      
   Heavy Snow/Sleet...   
   Snow will be winding down across the Southern Plains after 00Z=20   
   this evening (the start of the forecast period) but remain across=20   
   NM and of course farther east into AR/MO. This still supports an=20   
   astonishingly long swath of >6" of snowfall from NM to ME.=20   
      
   =46rom the Southern Plains through the Ohio Valley, 72-hr WPC   
   probabilities (so the entire forecast period although snowfall   
   should generally be a 24-hr period, a heavy band of snowfall on the   
   NW side of the low and within the strengthening jet streak will   
   support 1+"/hr snowfall as reflected by the WPC prototype snowband   
   tool. With this band likely translating along its long axis, heavy   
   snowfall will have a temporal extent sufficient for more than 8   
   inches (30-50% chance from the TX Panhandle through SW MO,   
   increasing to 90%+ in the Ohio Valley where more than 12 inches is   
   also likely (50-70% chance) before snow wanes from SW to NE on   
   Sunday. Locally 15+ inches is possible across southern OH.=20   
      
   The heaviest snow is likely from Pennsylvania through New England   
   where p-type changes are not likely. This is also where the longest   
   duration of heavy snowfall within both WAA banded structures and   
   then potentially a more pivoting/translating band will develop as   
   secondary low pressure skirts off the Mid-Atlantic coast and just   
   inside the Benchmark (40N/70W). This will support a longer   
   duration of 1-2+"/hr snowfall, and WPC 72-hr probabilities reach   
   above 70% for 12+ inches, and locally as much as 2 feet is possible   
   (especially in the Worcester Hills, Berkshires, and Catskills, as   
   well north of Boston along the coastal front) where WPC   
   probabilities for 24" are 10-30%. However, this will be a   
   widespread 12+" snowfall event for most of southern and central New   
   England as well as PA.   
      
   In addition, with the intense WAA, a warm nose aloft (generally   
   800-700mb) will gradually create a warm nose above 0C shifting   
   through the Mid-Atlantic, with additional warm nose/sleet impacts   
   expected from AR and into TN and KY. The cold depth below this warm   
   nose appears to be in many places above the 75th-90th percentile   
   for freezing rain, indicating primary sleet for these areas as   
   p-type transition occurs, with significant sleet accumulations of   
   multiple-inches expected. This will result in tremendous impacts to   
   travel in these areas.   
      
   The WSSI shows widespread Major Impacts (considerable disruptions   
   to daily life: dangerous to impossible driving conditions,=20   
   widespread closures, and disruptions to infrastructure) from the TX   
   Panhandle on east to the Ozarks, through the OH Valley, and all the   
   way to New England. Every major market along the I-95 metropolitan   
   corridor (Washington D.C. to Boston and even as far north as   
   Portland, ME) are expecting major impacts due to snow. The=20   
   D.C/Baltimore area on north to Philly and NYC are likely to see=20   
   some inclusion of sleet, but it will still result in significant=20   
   impacts when accounting for heavy snowfall that is expected to   
   exceed warning criteria (5-6"). A reminder that bitterly cold=20   
   temperatures will follow in wake of this storm through the middle=20   
   of next week throughout the eastern U.S., so snow/sleet impacts=20   
   will linger for many days even after precipitation ends.   
      
      
   Freezing Rain...   
   The most lasting impact will come as a result of significant to=20   
   locally catastrophic ice accumulations due to prolonged periods of=20   
   freezing rain. Just like the swath of >6" of snowfall, the areal=20   
   coverage of high chances (>50%) in WPC's ice probabilities=20   
   exceeding one-quarter inch of ice accumulation is expansive from=20   
   eastern TX through southern KY, with a secondary area east of the=20   
   Cumberland Gap from northern GA through southeast VA and including=20   
   much of the Carolinas. In these regions, at least 0.25" of ice is=20   
   expected to be widespread, with a more narrow corridor embedded=20   
   within of at least 0.5" (50-90%), highest in northern MS and=20   
   western TN, but some higher potential also exists in GA/SC where=20   
   locally more than 1 inch (a catastrophic accumulation for damage=20   
   and prolonged impacts of a week or more) is possible (10-30%=20   
   chance).   
      
   For LA, MS, TN, this ice accumulation is "additional" beyond what   
   will occur before 00Z (6pm CST), so local amounts above 1" are   
   actually expected to be more widespread than the updated   
   probabilities suggest. This produces a 20-40% chance of Extreme   
   impacts (extensive and widespread disruptions to infrastructure)   
   and these impacts could linger for a week or more where icing is   
   most significant. With very cold weather in place, this will become   
   a life-threatening situation, with potentially impossible travel   
   due to downed trees and power lines.   
      
      
   Key Messages for this system are linked below (Key Message 2).   
   Key messages for the widespread extreme cold are linked below as   
   well (Key Message 1).   
      
      
   ...Great Lakes...   
   Day 3...   
      
   Broad cyclonic flow will persist across the east, but an embedded   
   shortwave within this trough will dig out of Alberta Monday night   
   and then cross the Great Lakes from northwest to southeast during   
   Tuesday. This will enhance CAA, leading to another round of lake   
   effect snow (LES), although the duration and intensity of this   
   event should be modest overall, some moderate accumulations are   
   still expected beginning D3 /00Z Tuesday to 00Z Wednesday/ and   
   lingering beyond this forecast period. LES from Lake Erie should be   
   minimal as that lake is now ice covered according to GLERL, but   
   elsewhere, ***WPC probs...heaviest***   
      
      
   Snell/Weiss   
      
      
   ...Winter Storm Key Messages are in effect. Please see current=20   
    Key Messages below...   
      
   https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late=   
   stKeyMessage_1.png__;!!DZ3fjg!5yyp-eYgnqjdhXbnMGZ5F6MbfMH3V2jDjKFhtuPp72HzG=   
   v1utrZAGBCuWMZw740nbStEiOYlG4pGhUeyanMrSk83qWE$=20   
      
   https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late=   
   stKeyMessage_2.png__;!!DZ3fjg!5yyp-eYgnqjdhXbnMGZ5F6MbfMH3V2jDjKFhtuPp72HzG=   
   v1utrZAGBCuWMZw740nbStEiOYlG4pGhUeyanMrxvhmuX8$=20   
      
      
      
   $$   
      
   =3D =3D =3D   
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